Pilsung Taegyun AB A

Fathur Afif Hari Gary Dhika April Mulya Yusuf AB A A A AB AB AB AB

Anin Rizka A B

Dion Siska Mirel Hani Airita AB AB AB AB AB

www.telkomuniversity.ac.id Voice over Internet Protocol

Course Number : TTH2A3 CLO : 2 Week : 7 ext

www.telkomuniversity.ac.id Circuit Switch vs. Packet Switch

Connection less Connection Oriented

Circuit Switch Dedicated Path Message Switch ex: voice comm. at PSTN Packet Switch Any Path ex: data comm. at The Internet

• Connection less, both parties (Sender and Receiver) need to agree first before communication happen • Dedicated path, only 1 path (link) for 1 communication Q: How can we establish a voice communication using packet switch? A: Using VoIP, along with its signaling protocol SIP and H.323 Q: Why using packet switch? A: Better QoS, carrie any type of information, and accommodate future needs

www.telkomuniversity.ac.id Preface

• Voice uses analog signal, Packet Switch works on digital system. Thus, we need to transform analog voice into digital voice, using ADC (Analog to Digital Converter)

• Signaling Protocol uses TCP (Transfer Control Protocol • Signaling port on TCP: – H.323 uses port 1720 – SIP (Session Initiation Protocol) uses port 5060

www.telkomuniversity.ac.id Sample Architecture

IP Network

PC PC

Telepon IP Network PSTN Network

Gateway PC Telepon

Telepon

IP Network

Telepon Telepon Gateway Gateway PSTN Network PSTN Network

Telepon Telepon

www.telkomuniversity.ac.id VoIP Protocol

• Session Initiation Protocol (SIP) • Secure Real-time Transport Protocol (SRTP) • H.323 • Session Description Protocol (SDP) • Media Gateway Control Protocol (MGCP) • Inter-Asterisk eXchange (IAX) • Gateway Control Protocol (Megaco, H.248) • Jingle XMPP VoIP extensions • Real-time Transport Protocol (RTP) • Skype protocol • Real-time Transport Control Protocol • Teamspeak (RTCP)

The H.323 protocol was one of the first VoIP protocols that found widespread implementation for long-distance traffic, as well as local area network services. However, since the development of newer, less complex protocols such as MGCP and SIP, H.323 deployments are increasingly limited to carrying existing long-haul network traffic.

www.telkomuniversity.ac.id VoIP Elements

User Agent • any element that provides direct interaction with user to accommodate user’s need Proxy • a software that acts as VoIP server for user registration, authentication, and administration • also known as Soft Switch Protocol • Signaling for call setup, supervision, and clear down use TCP • Under supervision, RTP transfer already-packetized voice using UDP, while RTCP using TCP CODEC (Coder Decoder) • Used to transform analog voice into digital voice using certain characteristic, such as 64 kbps for G711 (H.323)

www.telkomuniversity.ac.id H.323

www.telkomuniversity.ac.id Preface

• H.323 is an ITU-T standard protocol to define real time multimedia communication via packet-based network, which has no SLG (Service Level Guarantee) • H.323 components: – Terminal or Customer End Point – Gateway connects with different network – (optional) Gatekeeper for call control – Multipoint Control Unit (MCU) for conferencing

www.telkomuniversity.ac.id Arsitektur Protokol H.323

User Data System Control/ Audio I/O Video I/O Applications User Interface Equipment Equipment T.120

System Control Session Layer Audio Codec and above H.245 Video Codec G.711, G.722, Control H.261 G.723.x, H.263 G.728, G.729

H.225 Call Control

H.225 Receive Path RAS Control

H.225 Layer

LAN Stack

www.telkomuniversity.ac.id SIP

www.telkomuniversity.ac.id Preface

• SIP is a IETF standard protocol for peer-to-peer signaling protocol

• Support HTTP and SMTP SIP SERVER • SIP components: PROXY REDIRECT – User Agent: REGISTRAR

• User Agent Client LOCATION • User Agent Server

Signaling Messages Between – Server User Agent And Server UAC UAC

UAS UAS

SIP USER AGENT SIP USER AGENT

www.telkomuniversity.ac.id SIP Messages

SIP has 2 types of messages: • Request, sent from client to server, which contain type of operation • Response, sent from server to client, which contain status information

Six types of request messages: • INVITE : shows an invitation to a user or service • ACK : shows a confirmation from a previous invitation • OPTION : used to query a server’s capabilities • BYE : sents by a user to terminate a communication • CANCEL : used to cancel a previous request • REGISTER : used to register a client in contact information

www.telkomuniversity.ac.id See you on next class

www.telkomuniversity.ac.id